1. Field of the Invention
The present invention relates to knifes for cutting and chopping crop materials, and more particularly pertains to a new beveled edge thin cutting knife for increasing the cutting effectiveness of agricultural crop harvesting and processing equipment.
2. Description of the Prior Art
Crop harvesting machines, such as combines and forage harvesters, often employ “heads” mounted on the front of the machinery to gather and cut the plant as it stands in the field at harvest time. Some types of heads, such as a head designed for use in the harvest of corn, includes a number of snouts, or finger-like structures that extend forwardly of the machine, to guide and gather the plants as they stand in rows in the field. The corn head also includes a number of knifes or blades that cut the upper portion of the plant off from the lower portion of the plant as the plant moves between the snouts, so that the upper portion of the plant can be processed by the combine while the lower portion of the plant remains in the field. The knives may be relatively thin, in that the thickness of the material used to form the knife is approximately 7 gauge steel sheet (approximately 0.179 inches) or thinner, with many of these knives having a thickness of 10 gauge (approximately 0.135 inches) or 12 gauge (approximately 0.104 inches). However, due to the relative thinness of the material used to form the knife, it has been relatively difficult, if not impossible, to effectively and economically produce a relatively sharp cutting edge on these knives for use on agricultural crop processing machinery. As a result, knifes formed out of material formed out of approximately 7 gauge or thinner material have not received a sharpened edge, and have featured a blunt cutting edge with a surface that extends substantially perpendicularly to the broad side faces of the knife for the full thickness of the knife material, such as is shown in FIGS. 1 and 2 of the drawings. The blunt cutting edge on the known thin knifes is not completely ineffective, as the relatively thin nature of the knife material and the teeth formed on the knife tend to do an acceptable job of cutting the crop material.
In particular, it has been established that it is relatively difficult to effectively and economically form a tapered or beveled edge onto the relatively thin material of these knives in the conventional manner for shaping knives formed of material thicker than 7 gauge, which is to using a milling machine. Further, when such milling is attempted, a relatively sharp and confined corner is necessarily created between adjacent teeth on the knife. In practical use of a knife formed using the milling technique, the sharp corner formed by the mill collects, and easily becomes clogged with, the crop materials that are being cut. This collection of crop material on the knife tends to reduce the effectiveness of the cutting capability of the adjacent teeth as the crop material is blocked from coming into contact with the blunt cutting edge.
Thus, there has been a need to improve upon the cutting effectiveness of the known blunt-edged thin cutting knifes, despite the problems that have been encountered in attempting to produce such knifes, in order to facilitate the cutting of crops in a manner that is more effective and efficient, and that requires less power to operate the crop processing apparatus.